Reasonably arrange selection of shielding equipment according to the project budget. The cell phone jammer equipment selection should pay attention to its shielding radius (i.e. power), performance stability, and lifetime and so on. The matching with the cell phone jammer whose radius is adjustable (i.e. the power is adjustable) should be considered according to the site situation. The matching with the directional antenna to control the main emission area (direction) of the shielding signal can also be considered.
1.1 Importance of installing cell phone jammer in the prison
The cell phone jammer will be more and more widely used for the popularity of the cell phone. As such mobile communication tool as the cell phone is gradually developing and popularizing and the technology level of the personal mobile communication means is gradually enhancing, especially after promotion and application of 3G technology, the negative effects of the cell phone in such places as the prison, labor reformatory, jail, addiction treatment center and so on become more and more obvious. Such mobile communication tools as the cell phone is absolutely forbidden in the jail, prison and so on. The ban is not just applied to the prisoner but also the supervision personnel.
Once the cell phone is brought into the prison and put into use, it is greatly harmful to management, safety and development of the prison. Some prisoners use the cell phone illegally transported to call and text in the prison to get the data, threaten the witness, even clique and organize the prison break and so on. Therefore, it becomes extremely urgent to install the cell phone jammer system in the prison occasions.
1.2 How to build the prison cell phone jammer system
1.2.1 Which factors should be considered when building the 3g cell phone jammer system?
•Influence from the base station
Currently, China Mobile, China Unicom and China Telecom have respectively built hundreds of thousands of base stations in China. The power and channel numbers of every base station are different. The distance between different base stations and prisons are different. It is normally suggested that there not be the base station within a range of 200-300m around the prison area where the cell phone jammer system is needed to be installed. If there is, influence from too small distance with the base station and too strong signal should be largely considered.